Rotary ore concentrator



Dec. 5, 1950 A. J. WEINlG 2,533,074

ROTARY ORE CONCENTRATOR Filed April 12, 1948 3 Sheets-Sheet. 1

J v fanz'enfrafe Add/ha 06/ DISC lar e JNVENTOR.

By AMY Weimig ATTORNEY Dec. 5, 1950 A. J. WEINIG 2,533,074

ROTARY ORE CONCENTRATOR Filed April '12, 1948 5 Sheets$hee.t 2

l. NM

l: .llllul lll IN V EN TOR.

4770E/VEY Dec. 5, 1950 A. J. WElNlG ROTARY ORE CONCENTRATOR 3 Sheets-Sheet? Filed April 12, 1948 V &.N,. Y m. 5 ma m WW m J M A M k F. 4/, Y B. m M I H 0 \PV 6 Patented Dec. 5, 1950 ROTARY ORE CONCENTRATOR Arthur J. Weinig, Golden, 0010., assignor to Colorado Iron Works Company, Denver, 0010.

Application April 12, 1948, Serial No. 20,472

This invention relates to improvements in rotary ore concentrators.

It is the object of this invention to produce a simple, substantial machine for concentrating ores, that shall be' highly efiicient in its operation and have a large capacity per unit weight. 7 Another object is to produce a machine of the type mentioned teat shall be so constructed that the fines from the centrifugal jigging and gravity concentration will be recirculated and subjected to a separate and final concentration employing both a downdraft and a centrifugal action. 7

.A further object is to produce a machine of the type specified that can be controlled in itsoperation to produce a very complete concentration or a'coarser one, as may be desired.

A further object is to produce machine of the type specified in which the fines are subjected as a final step to a down draft.

Another object is to produce a method and an apparatus of such construction that the objectionable teeter column problem is eliminated and, as a result, a greater proportion of the finer concentrate recovered.

In order to describe the method and. the machine in such a manner that the construction of the machine and its mode of operation can be readily understood, reference will now be had, to

the accompanying drawings in which the invention has been illustrated and in which:

Figure l is an assembly view showing the several parts in side elevation;

Figure 2 is a vertical diametrical section through the separating and classifying device;

Figure 3 is a fragmentary section, similarto that shown in Figure 2, and shows the fine concentrate circuit:

Figure 4 is a section similar to that shown in Figure 3 and shows the water circuit and the position of the fines during operation; and

Figure 5 is a transverse section taken on line 55, Figure 3.

Before proceeding with the description of the apparatus, certain terminology hereinafter employed must first be understood. The term ore comprises a mixture of particles of two general classes as to specific gravity or density, the first class being the lighter particles such as gangue, of relatively low density, and the second class being heavy particles, or concentrate, of relatively high density. The particles of the concentrate difier in size, the larger forming a coarse concentrate and the smaller 9. fin concentrate, or fines.

Referring now to the drawing reference numerals H3 designate the legs or base on which the machine is supported. Reference numeral H designates a stationary cylindrical casing and reference numeral 92 designates the conical bottom of the casing which will hereinafter at times be referred to as the base. lhe lower or apex I Claims. (Cl. 209'159) end of the conical bottom terminates in a discharge opening lt, that is connected with pipe 14, which connects it with the intake :port of concentrate pump ii that is driven from motor l6. Pipe ll connects the discharge port of pump I5 with the receiving compartment it of the dewaterer l9 which is positioned and arranged to overflow into the steady head tank 28. The fiow through pipe ii is controlled by a valve 2i. A pipe 22, provided with a valve 23, connects tank with the hydraulic water inflow opening 24. Interior of casing l l terminates in a bottom .25 which has a central opening that communicates the interior of the casing with water inlet chamber that has an inclined bottom 2? "provided with a central opening through which a short length of pipe 28 extends. The bottom of chamber 26 is also provided with a small port is which may be internal as shown in Figures 2 and 4, or external as shown in Figure 3, in the latter case it discharges into a, launder 3t.

Positioned within casing H is a drum 3! that is divided into an upper compartment A and a lower chamber B by a transverse partition 32.

Wall'33 of chamber B is somewhat smaller in outside diameter than the inside diameter of casing l l, leaving anannular space forming a sorting or teeter chamber 34 between the two for receiving a lower portion of a teeter column. Wall 33 is provided on its outer surface with a number of helical ribs 35 whose purpose and function will hereinafter appear.

Compartment A is surrounded by wall 36 that is somewhat smaller in outside diameter than wall 33, leaving an annular sorting or teeter chamber 31 that is somewhat larger than space 34 for receiving an upper portion of a teeter column.

The two compartment drum that has just been described is suspended from the lower end of shaft 38 that is mounted for rotation in a bearing block 39 by means of upper and lower antifriction bearings 49. Bearing block 39 has threaded engagement with the wall of opening 4! in the upper end of supporting bracket 42 that is secured to casin l l by bolts 63.

An electric motor s! is attached to bracket 42 and transmits rotation to shaft 38 by means of a V-belt 48, or other suitable transmission means. Bearing block 38 is provided with a hand wheel as by means of which it may be rotated to raise and lower the drum for adjusting the fineness of the separation in a manner that will later appear. The wall of threaded opening M is split and is forced against the outside of bearing block 39 by means of a screw 59 and a handle M for looking it in position.

The lower end of wall 33 has attached thereto, by welding or otherwise, a plate 52 that has a plurality of radial impeller blades 53 and a central opening 54. lVall 33 has a row of openings 55,

wardly flowing current of water.

3 positioned just behind ribs 35 to prevent choking of the teeter column by the fine concentrate. The upper end of casing H is surroundedby a wall 55 that terminates in a spout 58. Water and ore are fed into compartment A through a pipe 59 or through a, suitable launder similarly situated. Air is introduced to the lower end of pipe 28 when desired through a pipe 8%].

Ribs 35, a few of which are positioned on the outer surface of wall 33, give an upward component to the water and in addition produce a pulsation that results in a jigging or teetering action which further enhances the concentration.

Sincethe fines that are separated must all flow downwardly through hole 54 and through pipe 28, when the drum is in its lowermost position, a very thorough separation takes place. By means of hand wheel 49, bearing block 39 may be rotated and the drum raised or low'ered. When the drumis raised, more of the fines from annular chamber 34 will pass into pipe 26 without first passing through the toroidal circuit which increases the rate at which the ore is L-et us now assume that the machine which has been illustrated and described is in operation and that the parts aretarra'nge'd as in Figures 1 and 2 Bothrnotors l 'fi an'd 141 are operating and waterand ore fedto compartment A through pipe 59. After the dewaterer has been filled with water so that it overflows, the operation commences. The ore that is fed to compartment A flows outthrou 'gh.ho1es 6l into the an nular teeter chamber 31 where it meets an up The water in annular chambers 34 and 31 has a helical path, due to the rotation of the drum and the action of ribs 35. The water and the lighter gangue particlesmove upwardly and overflow the upper end of wall I I, as indicated by arrow 62. The heavier metalliferousconcentrate "moves downwardly into annular chamber 34, as indicated lioy arrow 63. Practically all of the downwardly movingfin e "concentrate passes through ,holes 55 into compartment B, following arrows '63, as

shown in Figure 3, and finally passes through hole 54. 'A portion of the aforesaid fine'concentrate fpasses downwardly hrough pipe '28 and into discharge opening 13, and thence into "pipe l4 pumpflb from whichit is elevated to the dewaterer IS. The fine concentrate that does not fall through pipe 28 is'recirculated b'yfthe action of the impeller blades 53 througha toroidal path and enters a second 'timeinto compart- 'scribed is a rotary ore concentrator "or a type early 'suggested'by Wetherbee. .See U. S. Patent No. 856,612, In this process the jor'e particles are kept in horizontalrotary agitation jagainst an :upward current of hydraulicfwate'r, just sufiicient'to'carry overthe top of the container the gangue particles and permit the heavy grains of mineral 'to 'settle to the bottom where means "are provided for discharge.

In'the type of apparatus to which U. S. Patent 856,612 belongs, the 'operation is at its best when the'discharge launder or hopper at the bottom is kept fullof I concentrate so that the discharge is much restricted by the concentrate itself. Under this 4 condition chambers corresponding to 34 and 65 become filled with heavy solids largely made up of tine concentrate which is unable to settle down through the ascending current of water. Eventually the accumulation is great enough to restrict the void spaces between the coarser concentrate grains through which the ascending hydraulic water travels, to such a degree that the velocityof the water through these spaces becomes great enough to carry the finer grains of concentrate up and over the top of apparatus Where they are lost. Such a zone of accumulation is known in the art as a teeter bed or column. It presents a serious problem in all forms of hydraulic concentration and classification. v I V The present invention has resulted 'froin'st'udy .of the teeter -column problem and offers a solution for the "elimination of such column and for the recovery of the finer concentrate ordinarily lost because of the teeter c'olurn'n effects. I

v The circling fiowthrough opening 54 is positioned ov'er the'down draft flow of Water in pipe 28 and near 'the' inflow from chamber 26. Here the three flows mentioned comingle and a substantial portion of the'fine solids from'the teeter column is shunted out of the system and recovered; a'ccurn'ula'tions "in "the teeter column are u u d- The suspension )of fine concentrateiin the liquid from the teeter column isdue to the vic ence of 'the agitation and circulation. Ordinarily these particles'arie from 28 mesh'down to 100 mesh or even finer when very heavy minerals like 'g'ale'na are present. 4 I

The, coarser concentrate does not follow -the 'jci'rculation within the bottom of the drum but takes a path'down through'chambers 34 and 65 and then out of the system. This path is the ordinary fp'ath "taken by the concentrate "in "this type of concentration, perhaps with the excepjtion that'this coarse ooneentrate dis'chargesfrom the structure of "this'irive'ntion' much cleaner and freerofgangue It is believed 'that this is due to the increased jhydr'aulic cleaning [effect in chambers "65 and3 '4 because of the recirculation.

Qtherstructures shown in this invention includerath'er widely sp afced spiral ribs' 3 5 sopositiolnedfa's -tpjadhl an upw'a'rd compenent to the agitation. This assistsin'preventing the solids in chamber 34 "in "becoming compacted and dense, The ribs also provide ashield justbehind which openings 55 areplaced where i-t'has been found the "openings so positioned do not cholre withcoarse material and where the circu- "lation oftheliq'uid nomthe teeter column is more free Further, the ribs establish *a irel'quency of jigging or pulsation which is impressed on the air chamber B in apecul'iarway. GO.

Sihcethe vertex of 'the'bottorn surface of the' air 'is nearopening'fui 'a'gulping action of the frequency mentioned, fdevelops by impellerfaction "'asfthe impeller tends to :suck air and then releases ,lit. causes an expansion and con-- 1 traction of th air in" chamber B which affects the entire pulp contents of the apparatus and enhances (the jigging "action.

4 Thecom'binationfof'recirculation, upward'agitation and jigging yields'a very free sorting zone in chamber 34. The specific gravity of the pulp jin this zonehas never been found greater than 1.75.

b With 'mostjores 'sufiicient air 'is'held in chamber'B without 'airaddition. This probably is maintained by entrained air "in the'circulatingwater. However, if'fiecessary asmallamourit of air may be added through pipe 68. Only sufficient is needed to maintain the air space in chamber 13.

Another feature to be noted is the entry of the hydraulic water through an annular space around the down draft pipe 28. Note that the inlet chamber 26 has an inclined bottom terminating in opening 29. The purpose of this opening is to remove any accumulation of heavy solids which may enter the chamber. These solids ordinarily are only small flakes of iron or bits of other metal and occasionally coarse gold. In the latter case if the gold is in suflicient amount it may be separately recovered by making the opening 29 external as shown in Figure Still another structure to be noted is means for vertically positioning the rotating drum 3! above the bottom of easing ll. It affords a most sensitive and critical means of adjustment. For example when positioned at the lowest point it is easily possible to extract from the system, only the fine concentrate from the teeter column and under this condition the coarser and heavier ore grain can be discharged out and over the top of the apparatus. The fine concentrate is surprisingly clean and free of gangue.

By raising the drum more and more, coarser and coarser concentrate will be extracted from the chambers 34 and 65 and under ordinary conditions of water inflow in operation it is quite possible to discharge through pipe 28 the entire feed to the machine. However, quite independent of the position of the drum the line concentrate circuit from the teeter column remains functional and unaffected. It can be readily seen, therefore, that a most sensitive means of adjustment is thus afforded, whereby selection of quality or quantity of product can be quickly attained.

As an example of this performance, a very difficult product known as Patrick Pond tailings from treated taconite iron ores of Cooley, Minnesota, has yielded the following results in experiments to produce therefrom a marketable iron ore concentrate of 58% Fe (iron) with not over 11% Si02 (silica). This product is all -4 mesh.

Concentrate Recovered Opening below Drum Per Cent Per Cent Per Cent Weight 1 Fe slo 1 Per cent of the feed weight.

A screen analysis of the following:

the concentrate showed In this test having once set the hydraulic water flow to what appeared was the best condition, the various qualities and quantities of con centrate made were produced solely by the positioning the drum above the bottom of casing ii.

' sizes normally lost from Since the Patrick Pond tailings are mainly classifier overflows, special note is to be made of the heavy recoveries made by this process in teeter column accumulations.

Having described the invention what is claimed as new is: Y r

l; A method of separating ores containing light particles, such as gangue, a coarse concentrate, and a fine concentrate, comprising; confining a teeter column in a substantially annular zone with the axis of the teeter column disposed substantially vertically, supporting the bottom annular area of the teeter column, applying rotating forces tothe inner surface of the teeter column and feeding water into the teeter column producing a spirally upward movement of water in the zone, the upward movement of the water carrying light particles upwardly for discharge from the upperend of the zone and the concentrates moving to the lower end of the zone, by-passing a portion of fine concentrate from the teeter column above its lower end man inward direction and thence downwardly, discharging coarse concentrate inwardly from the lower end of the teeter column and thence downwardly, recirculating a portion of the downwardly moving fine concentrate into the lower end of the tester column for passage upwardly therethrough, and discharging a portion of the downwardly moving fine concentrate with the downwar ly moving coarse concentrate by the action of an outgoing current of water,

2. An ore concentrator comprising; a hollow i rotor mounted for rotation about a substantially vertical axis, the rotor having an opening at its bottom, a casing surrounding the rotor in spaced relation thereto providing a teeter chamber between the rotor and casing for containing a teeter column therein, wall means extending inwardly from the casing below the rotor at the bottom of the teeter chamber for supporting a teeter column thereabove, means for feeding ore and water into the teeter column, aperture means in the rotor disposed above its bottom for permitting fine concentrate in the teeter column to pass inwardly therethrough, discharge means having an opening in the wall means disposed below the bottom of the rotor adapted to receive an outgoing current of water, said wall means and the bottom of the rotor forming a passageway through which a portion of the line concentrate may recirculate into the lower end of the teeter column for passage upwardly therethrough and through which coarse concentrate may pass to said last named opening, a portion of the fine concentrate being adapted to pass out with the outgoing current of water, and means for recirculating said first named portion of-the fine concentrate outwardly through'said passageway and into the lower end of the teeter column.

3. An ore concentrator comprising; a hollow rotor mounted for rotation about a substantially vertical axis, the rotor having an opening at its bottom, a casing surrounding the rotor in spaced relation thereto providing a teeter chamber between the rotor'and casing for containing a teeter column therein, wall means extending inwardly from the casing below the rotor at the bottom of the teeter chamber for supporting a teeter column thereabove, means for feeding ore and water into the teeter column, aperture means in the rotor disposed above its bottom for permitting fine concentrate inthe teeter column to pass inwardly therethrough, discharge means having an open-ingin the wall means disposed below the bottom of the rotor adapted to receive an outgoing current of water, said wall means and the bottom of the rotor forming a passageway through which a portion of the fine concentrate may recirculate into the lower end of the teeter column for passage upwardly therethrough and through which coarse concentrate may pass to said last named opening, a portion of the fine concentrate being adapted to pass out with the outgoing current of water, means for recirculating said first named portion of the fine concentrate outwardly through said passageway and into the lower end of the teeter column, and means for varying the size of said passageway.

4. An ore concentrator comprising; a hollow rotor mounted for rotation about a substantially vertical axis, the rotor having an opening at its bottom, a casing surrounding the rotor in spaced relation thereto providing a teeter chamber between the rotor and casing for containing a teeter column therein, wall means extending inwardly from the casing below the rotor at the bottom of the teeter chamber for supporting a teeter column thereabove, means for feeding ore and water into the teeter column, aperture means in the rotor disposed above its bottom for permitting fine concentrate in the teeter column to pass inwardly therethrough, discharge means having an opening in the wall means disposed below the bottom of the rotor adapted to receive an outgoing current of water, said wall means and the bottom of the rotor forming a passageway through which a portion of the fine concentrate may recirculate into the lower end of the teeter column for passage upwardly therethrough and through which coarse concentrate may pass to ,said last named opening, a portion of the fine concentrate being adapted to pass out with the outgoing current of water, means for recirculating said first named portion of the fine concentrate outwardly through said pas sageway and into the lower end of the teeter column, and means for controlling the rate of flow through said discharge means.

-5. An ore concentrator'comprising; a hollow rotor mounted for rotation about a substantially vertical axis, the .rotor having an opening at its bottom, a casing surrounding the rotor :inspaced relation thereto providing a teeter chamber betweenthe rotor and casing for containinga-teeter column therein, wall means extending inwardly from the casing below the rotor at the bottom of the teeter chamber for supporting a teeter column thereabrove, means for feeding ore and water into the teeter column, aperture means in the rotor disposed above its-bottom for permitting fine concentrate in the teeter column to pass inwardly therethrough, discharge means having an opening in the wall means disposed below the bottom of the rotor adapted to receive an outgoing current of water, said wall means and the bottom of the rotor forming a passageway through which .a portion .of the fine concentrate mayrecirculate into the lower end .of the teeter column for passage upwardly there- .through and through which coarse concentrate may :pass to said last :named opening, a-portion of the fine concentrate being adaptedtolpass out with the outgoing current of water, means for recirculating said first named portionof the fine concentrate outwardly through -said ;passageway and into the lower end of the teeter column, and means for delivering water'into-said passageway.

'6. An ore concentrator comprising; a hollow rotor mounted for rotation about a. substantially vertical axis, the rotor having an opening at its bottom, a casing surrounding the rotor in spaced relation thereto providing a teeter chamber between the rotor and casing for containing a teeter column therein, wall means extending inwardly from the casing below the rotor at the bottom of the teeter chamber for supporting a teeter column thereabove, means for feeding ore and water into the teeter column, aperture means in the rotor disposed above its bottom for permitting fine concentrate in the teeter column to pass inwardly therethrough, discharge means having an opening in the wall means disposed below the bottom of the rotor adapted to receive an outgoing current of water, said wall means and the bottom of the rotor forming a passageway through which a portion of the fine concentrate may recirculate into the lower end of the teeter column for passage upwardly therethrough and through which coarse concentrate may pass to said last named opening, a portion of the fine concentrate being adapted to pass out with the outgoing current of water, means for recirculating said first named portion of the fine concentrate outwardly through said passageway and into the lower end of the teeter column, and means for adding air to the inside of the rotor.

7. A rotary concentrator comprising, a stationary substantially cylindrical housing having a discharge outlet at its lower end, a bearing positioned above the housing in axial alignment therewith, a shaft mounted for rotation in the bearing, means resisting forces tending to move the shaft axially in the bearing, a cylindrical drum secured in axial relation to the lower end of the shaft, within the housing, the outside diameter of the drum being less than the inside diameter of the housing whereby an annular teeter chamber is formed between the two, means for feeding ore onto the top wall of the drum while it is rotating, the lower end of the drum having a closure provided with a central opening and a plurality of radial impeller blades, the peripheral wall of the drum having a plurality of holes above and adjacent the lower end closure, 'a tubular discharge pipe positioned below the central opening of the lower end closure, and means for feeding water into the housing below the lower end of the drum and into the space surrounding the discharge pipe, whereby the liquid from the teeter chamber will be recirculated by the action of the rotating drum and subjected to a concentrating action by the upward flow of water.

8. A rotary concentrator comprising, a stationary substantially cylindrical housing having a discharge outlet at its lower end, a bearing positioned above the housing in axial alignment therewith, a shaft mounted for rotation in the bearing, means resisting forces tending to move the shaft axially in the bearing, means for adjusting the bearing and shaft vertically, a drum secured to the lower end of the shaft, within the housing, the drum'having a transverse partition dividing it into an upper and a lower chamber, the outside diameter of the drum being less than the inside diameter of the housing whereby an annular teeter chamber is formed between the two, the wallof the upper chamber having a pluralityof openings adjacent the transverse partition, means for feeding ore into the upper chamber, means for rotating said shaft and drum, the lower end of the lower chamber having a closure provided with a center opening and a plurality of radial impeller blades, the wall of the lower chamber having a plurality of holes above and adjacent the closure, a tubular discharge pipe positioned below the center opening in the closure, and means for feeding water into the housing below the lower end of the rotating drum and into the space surrounding the discharge pipe, whereby the liquid from the teeter chamber will be recirculated by the action of the lower portion of the drum and subjected to the concentrating action of the upward flow of water.

9. A machine for separating ore, comprising, in combination, a base, an upwardly opening cylindrical receptacle supported thereon, a bracket extending upwardly from said receptacle, the upper end of said bracket having an opening coaxial with the receptacle, a bearing in said opening, means for adjusting the position of the bearing axially, a shaft mounted for rotation in the bearing, means resisting forces tending to move the shaft longitudinally in the bearing, a drum of substantially cylindrical cross section, secured to the lower end of the shaft and positioned in the receptacle, said drum having a transverse partition dividing it into an upper and a lower chamber, the wall of the upper chamber having a plurality of openings adjacent the upper surface of the partition, the lower end of the lower chamber having a closure provided with a center opening and a plurality of impeller blades, the wall of the lower chamber having a plurality of openings above and adjacent the closure, the outside diameter of the drum being less than the inside diameter of the receptacle whereby an annular sorting chamber is formed, means for flowing water upwardly through the sorting chamber, a tubular discharge outlet underneath the center opening of the bottom of the lower chamber, and means for feeding ore and water to the upper chamber.

10. An ore concentrating and separating machine comprising, in combination, a base having a downwardly tapering compartment separated into an upper and a lower chamber by a partition having an opening concentric therewith, a section of pipe passing through the opening, coaxial with the conical compartment, the upper end of the upper chamber having an inwardly directed 10 flange whose opening is larger than the outside of the pipe forming an annular water outlet, means for introducing water into said upper chamber, a cylindrical receptacle extending upwardly from the top of the conical base, a bracket projecting upwardly from the cylindrical receptacle having its upper end overhanging the receptacle, a threaded opening in said upper end, coaxial with the receptacle, a tubular bearing block in said opening mounted for rotation and axial adjustment therein, means for clamping said bearing, a shaft mounted for rotation in the bearing block, means resisting forces tending to move the shaft axially in the bearing, a substantially cylindrical drum secured to the lower end of the shaft for rotation within the receptacle, the outside diameter of the drum being less than the inside diameter of the receptacle providing an annular sorting chamber, the drum being divided into an upper chamber and a lower chamber by a transverse partition, the wall of the drum having a plurality of openings adjacent the upper surface of the partition, the lower end of the lower chamber of the drum having a closure provided with an opening concentric therewith, said closure having a plurality of radial impeller blades, the wall of the lower chamber having a plurality of openings positioned between the partition and the closure, the wall of the lower chamber being otherwise imperforate, means for feeding ore to the upper chamber in the drum and simultaneously flowing a stream of water upwardly through the sorting chamber, and means for turning the drum.

ARTHUR J. WEINIG.

REFERENCES CITED f'he following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 856,611 Wetherbee June 11, 1907 856,612 Wetherbee June 11, 1907 1,163,876 Wetherbee Dec. 14, 1915 1,934,406 Coe Nov. 7, 1933 2,174,553 Darman Oct. 3, 1939 2,422,203 McNeill June 17, 1947 

1. A METHOD OF SEPARATING ORES CONTAINING LIGHT PARTICLES, SUCH AS GANGUE, A COARSE CONCENTRATE, AND A FINE CONCENTRATE, COMPRISING; CONFINIG A TEETER COLUMN IN A SUBSTANTIALLY ANNULAR ZONE WITH THE AXIS OF THE TEETER COLUMN DISPOSED SUBSTANTIALLY VERTICALLY, SUPPORTING THE BOTTOM ANNULAR AREA OF THE TEETER COLUMN, APPLYING ROTATING FORCES TO THE INNER SURFACE OF THE TEETER COLUMN AND FEEDING WATER INTO THE TEETER COLUMN PRODUCING A SPIRALLY UPWARD MOVEMENT OF WATER IN THE ZONE, THE UPWARD MOVEMENT OF THE WATER CARRYING LIGHT PARTICLES UPWARDLY FOR DISCHARGE FROM THE UPPER END OF THE ZONE AND THE CONCENTRATES MOVING TO THE LOWER END OF THE ZONE, 